Field of the Invention
One disclosed aspect of the embodiments relates to an electro-photographic image forming apparatus such as a laser beam printer, a copying machine, and a facsimile.
Description of the Related Art
In recent years, Japanese Patent Application Laid-Open No. 2013-254173 discusses a technique for optimizing the potential of a portion to which toner on a photosensitive member is not adhered, so as to further improve the image quality of an electro-photographic image forming apparatus. More specifically, the technique irradiates an image portion to which toner on the photosensitive member is adhered, with light having a first light emission amount for obtaining a potential at which toner adheres. The technique further irradiates a non-image portion to which toner on the photosensitive member is not adhered, with light having a second light emission amount smaller than the first light emission amount for obtaining a potential at which toner is not adhered.
Japanese Patent Application Laid-Open No. 2013-254173 discusses performing Automatic Power Control (APC) in an adjustment process for adjusting two different levels of light emission amounts (the first light emission amount and the second light emission amount) to stabilize the first and the second light emission amounts, and a sequence in the adjustment process from reception of an image forming instruction until before exposure of a photosensitive member to light.
Japanese Patent Application Laid-Open No. 2013-254173 discusses that, in a sequence in the adjustment process, APC for the second light emission amount and APC for the first light emission amount are alternately performed. Alternately performing APC in this way may cause an overshoot of a drive current supplied to a semiconductor laser light emitting unit. A drive current exceeding the rating of the semiconductor laser due to an overshoot may cause failure of the semiconductor laser.